Establishment of a transgenic cell line with stable expression of human CD14 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish a transgenic cell line with stable expression of CD14.</p><p><b>METHODS</b>Total RNA extracted from peripheral blood mononuclear cells was treated with RNAase-free DNAase, the human CD14 gene was cloned and sequenced through the RT-PCR, T-A clone techniques and ABI PRISM377 machine. Eukaryotic expression vector pcDNA3.1(+)/CD14 was constructed by cleaving with double restriction endonucleases EcoR I/Xba I and ligating with T4 ligase. The human cervical cancer cell line Hela was transfected with the positive recombinant plasmid pcDNA3.1(+)/CD14 using superfect transfection reagent. Positive clones were selected by G418 at a concentration of 0.5 μg/μl and the expression of human CD14 on the transfected Hela cells was confirmed by quantitative PCR and immunofluorescent assay.</p><p><b>RESULTS</b>There was significantly difference om expression of CD14 mRNA between the blank pcDNA3.1(+) transfected cells and pcDNA3.1(+)/CD14 transfected cells (P<0.01). The fluorescence was significantly stronger on the stable cell line Hela-CD14 than that on the transiently transfected Hela cells,and no visible fluorescence was observed in blank vector transfected cells.</p><p><b>CONCLUSION</b>The transfectant cell line Hela-CD14 with stable expression of human CD14 has been successfully established, which can be used to study human CD14 molecular and CD14-associated monocyte/macrophage cell diseases.</p>

Targeted killing of the Nalm-6 cells with 2E8-Genistein immunotoxin and its mechanism / 中华儿科杂志

<p><b>OBJECTIVE</b>Leukemia is the most common hematopoietic malignancies in children. Chemotherapy is currently the primary modality of treatment for this fatal disease. Although chemotherapy is very effective in terms of cell killing, severe side effects such as severe infections, intracranial hemorrhage etc. are frequently encountered due to its poor selective damage between normal and malignant cells or tissues. Thus, a new therapy with highly selective killing of malignant cells which leaves the normal cells unaffected is desperately desired. The aim of this study was to investigate the targeting efficacy in vitro with a new clone of anti-human CD19 antibody immunotoxin 2E8-Genistein on B lineage leukemia cell line Nalm-6 cells and its mechanisms in order to provide the evidence of target therapy on B lineage leukemia and lymphoma.</p><p><b>METHODS</b>2E8-Genistein immunotoxin was generated by conjugating Mab 2E8 with a tyrosine kinase inhibitor, Genistein (Gen) via the Sulfo-SANPAH, an ultra-violet sensitive reagent. Nalm-6, a CD19+ B cell leukemia cell line, was used as target cells, while Molt-3, a CD19-T cell leukemia cell line, was taken as the negative control. The morphology of the cells was observed under the reverted reversed light microscope and the viability was checked with either trypan blue exclusion or MTT methods. Two-color flow cytometry was applied to study the mechanism of cell killing.</p><p><b>RESULTS</b>After 24 hours of culture, 2E8-Genistein showed marked target killing on Nalm-6 cells at nine different concentrations from 20 nmol/L through 100 nmol/L with cell survival rates from (71.8 +/- 7.9)% down to (16.6 +/- 12.9)%, respectively (n = 3), which were all significantly lower than that of control group (100 +/- 13.9)% (P < 0.05). The killing effect was even more significant when the concentration was over 80 nmol/L. The growth inhibition rates of this immunotoxin on Nalm-6 cells were 82%, 84% and 94%, respectively at 24, 48 and 72 hours of culture in a time dependent manner. Significant difference was observed between the cell growth curve of Nalm-6 cultured with 100 nmol/L of 2E8-Gen and those of Nalm-6 cultured with medium (blank), PBS (negative control) or the same concentration of pure 2E8 antibody (negative control) groups (F = 152.15, P = 2.15 x 10(-7)), but there was no significant difference among the three control groups (F = 1.51, P = 0.29). When Molt-3 cells were used as target cells, the cell growth curves of Molt-3 cultured with 2E8-Gen (100 nmol/L) and with negative control of blank did not show any significant difference (F = 0.34, P = 0.59). PI/FITC Annexin V double staining analysis with flow cytometry showed that the positive rate (33.45 +/- 8.77)% of early apoptosis on Nalm-6 cells induced by 100 nmol/L of 2E8-Genistein was significantly higher than that of negative control of blank (10.44% +/- 1.28%, t = -4.39, P = 0.001) at 24 hours of culture.</p><p><b>CONCLUSION</b>2E8-Genistein immunotoxin can significantly target the Nalm-6 cells in vitro in a time response manner and the apoptosis induction is involved in the course of this killing effect.</p>

Eukaryotic expression and determination of ZCH-7-2F9 single chain antibody against human CD14 / 中华儿科杂志

<p><b>OBJECTIVE</b>Acute monocytic leukemia (AML)-M5 is the common type of acute myeloid leukemias in children. Studies have shown that there are abundant lipopolysaccharide (LPS) receptor (designated as CD14) molecules on the cell membrane of M5 cells and they play an important role in the diagnosis of M5, since they can be recognized and bound by mouse-anti-human CD14 monoclonal antibody (McAb). However, mouse-originated antibodies are largely not suitable for clinical application due to the severe side effects, thus "humanized antibody" is desired. As the first step for developing humanized antibody, the construction and expression of single chain antibody (scFv) with functional protein are necessary. The present study aimed to express ZCH-7-2F9 ScFv (scFv(2F9)) in eukaryotic cells and obtain the scFv(2F9) protein with a high biological activity.</p><p><b>METHODS</b>Four primers were synthesized to construct the eukaryotic expressional vector, which included SfiI and EcoRI enzyme cleaving site, 6 x His and stop code TGA sequences. scFv(2F9) gene was amplified through splicing by overlap extension (SOE) using the high fidelity Taq polymerase. Positive recombinants (pSectag2A/scFv(2F9)) were identified through enzyme cleaving and sequenced before expression and were transformed into Chinese hamster ovary (CHO) cells for expression. Western-Blot and flow cytometry (FCM) were carried out to determine the relative molecular mass (Mr) and binding activity of scFv(2F9).</p><p><b>RESULTS</b>The cloned scFv(2F9) gene was identified to be functional by sequencing and expressing. The interested protein could be detected in the culture supernatant of transformed CHO cells with an Mr of 31 000. The blocking test showed that the positive cell percentages, the mean fluorescence intensity (MFI) and the peak of channel (peak Ch) were reduced by 90.02%, 63.30% and 63.38%, respectively after blocking with scFv(2F9), while those were 4.55%, 10.09% and 5.02% after blockage using the supernatant from the CHO cells transfected with blanked vector pSectag2A.</p><p><b>CONCLUSIONS</b>The scFv(2F9) against human CD14 antigen was successfully expressed in eukaryotic cells and showed a high biological activity, which may be useful for the further studies on its humanized antibodies.</p>

Construction and expression of prokaryotic vector of single chain antibody derived from a new clone of anti-CD14 antibody ZCH-7-2F9 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To construct a prokaryotic vector of ZCH-7-2F9 single chain antibody (ScFv2F9) and to obtain the ScFv2F9 protein with biological activity for further studies.</p><p><b>METHODS</b>Primers were synthesized according to the gene sequence of ScFv2F9, four tandem glycin and one serine (G4S) 3linker and multiple cloning site(MCS) of pIVEX2.3-MCS vector, which included NdeI and SmaI enzyme cleaving sites. ScFv2F9 gene was amplified through splicing by overlap extension (SOE) using the high fidelity Taq polymerase. Then the gene was cloned to pGEM-T easy and pIVEX2.3-MCS vectors. Positive recombinants (pIVEX2.3-MCS/ScFv2F9) were identified through enzyme cleaving and sequenced before expression. The recombinant plasmids were transfected into E.coli BL21star(DE3)plysS for expression. After purification with Ni+resin and renaturation in vitro, the relative molecular mass (Mr) and the binding activity of the interesting protein were determined by SDS-PAGE and flow cytometry (FCM), respectively.</p><p><b>RESULT</b>The cloned ScFv2F9 gene was identified to be functional by sequencing and expressing. The interesting protein was detected in inclusion body with a Mr of 31 000. The blocking test showed that the positive cell percentage, the mean fluorescence intensity (MFI) and the peak of channel (peak Ch) were reduced by 11.73%, 11.96% and 31.57%, respectively after once blockage by scFv2F9 protein, and 26.44 %, 21.75 % and 42.11 % after blockage twice.</p><p><b>CONCLUSION</b>The ScFv2F9 against human CD14 antigen has been successfully expressed in prokaryotic cells with partial biological activity, which lays the foundation for further studies on its immunotoxin and other kinds of engineered antibodies.</p>

Long-term follow-up of treatment outcome and prognosis on 46 children with acute promyelocytic leukemia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Acute promyelocytic leukemia (APL) is a specific type of hematopoietic malignancy, accounting for 10% of the de novo acute myeloid leukemia (AML). The data on long-term outcome of APL in children are limited. The aim of this study was to investigate the clinical biological features, diagnosis, prognosis and long-term survival of childhood APL.</p><p><b>METHODS</b>A total of 46 children with newly diagnosed APL from April 1998 to October 2005 were enrolled into this study. Induction treatment containing all-trans retinoic acid (ATRA) plus daunorubicin (DNR) or pirarubicin (THP) was performed on these patients, followed by 6 courses of chemotherapy consolidation: DNR, homoharringtonine or etoposide plus Ara-C. A maintenance therapy was then administered once 3-6 months. The total period of treatment was 2.5 years.</p><p><b>RESULTS</b>Of the 39 patients who had completed the regular treatment, 36 (92.3%) achieved a complete remission. The 5-year cumulative incidence of relapse (CIR) was 28.6%. The estimated overall survival (OS) rates at 1, 3 and 5 years were (86.1 +/- 5.8)%, (76.1 +/- 7.5)% and (70.2 +/- 8.9)% respectively, while the event free survival (EFS) rates were (78.4 +/- 6.8)%, (63.6 +/- 8.7)% and (53.1 +/- 10.0)% respectively. The 5-year OS rate of patients with WBC less than or equal to 10.0 X 10(9)/L was (81.4 +/- 10.3)%, which was significantly higher than that with WBC greater than 10.0 X 10(9)/L[(51.6 +/- 14.7)%, P < 0.05]. Five patients with RT-PCR positive for PML/RARalpha S (short) subtype died eventually although all of them achieved CR, but none of the 13 patients with PML/RARalpha L (long) subtype died.</p><p><b>CONCLUSIONS</b>Remission induction therapy with ATRA + DNR or THP is effective and safe for newly diagnosed childhood APL. The remission induction therapy combined with chemotherapy containing high/intermediate dose Ara-C can improve the long-term survival rates of APL patients. High WBC count and S subtype of PML-RARa are two poor prognostic factors for children with APL.</p>

Cloning and sequencing of VL and VH genes from a novel clone ZCH-7-2F9 of anti-hCD14 monoclonal antibody / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To acquire the genes of light chain variable region (VL) and heavy chain variable region (VH) of a novel clone ZCH-7-2F9(2F9) of anti-hCD14 for construction of anti-hCD14 single chain antibody(ScFv).</p><p><b>METHODS</b>From the mouse hybridoma cell line 2F9 and its fusion partner murine myeloma cell line NS-1, total RNA was prepared. The VL and VH genes were amplified by RT-PCR with family specific primer pairs, respectively. The PCR products were cloned into pGEM(sound recording copyright sign)-T Easy vectors, then transfected into DH5alpha and the positive recombinants were identified and purified. After sequencing with automatic DNA sequencer the sequences were analyzed online.</p><p><b>RESULTS</b>VL gene of the new clone of CD14 monoclonal antibody (McAb) 2F9 consisted of 321 bps encoding a peptide of 107 amino acid residues, and VH gene of the 2F9 antibody contained 360 bps encoding a peptide of 120 amino acid residues. According to IMMUNOGENETICS online analysis by IMGT/V-QUEST, the VL and VH genes belonged to mouse IGKV and mouse IGHV subgroups, respectively. On the position 23/88 of the light chain and 22/96 of the heavy chain genes there were cysteines, which play the key role in forming disulfo-bond in each chain. Both VL and VH chains had definitely 4 frame regions (FR) and 3 complementary determinant regions (CDR).</p><p><b>CONCLUSION</b>The treatment of CML consisting of myeloablative Allo-SCT combined with Gleevec before and after transplantation is an effective and safe method for CML.</p>

Evaluation of the P-gp pump function on leukemic cell membrane and proper application of its reversal agents with Calcein-AM and flow cytometry / 中华儿科杂志

<p><b>OBJECTIVE</b>Leukemia is the most common malignancy in children. Combined chemotherapy is currently the primary treatment modality. During the past decade, very high cure rates of childhood acute lymphoblastic leukemia (ALL) have been reported both at home and abroad. However, the cure rates of children with acute myeloid leukemia (AML) remain low due to the multiple-drug resistance (MDR). P-glycoprotein (P-gp) is one of the most important mechanisms of MDR for leukemia cells. However, the function of the protein, the clinical application of its reversal agents and the efficacy of the combination of the reversal agents remain to be elucidated. The present study aimed to evaluate the P-gp pump function on leukemia cell membrane and the effects of the combined administration of the reversal agents cyclosporin A (CSA) and verapamil (VER) through the observation of Calcein-AM (C-AM) metabolism in the cell line K562 and its multi-drug resistant subline K562/VCR.</p><p><b>METHODS</b>The mean fluorescence intensity (MFI) of C-AM inside the cytoplasm was analyzed with flow cytometry (FCM). The events of K562 and K562/VCR cells treated and untreated with CSA, VER and CSA + VER were acquired at time points 0, 30, 60, 90 and 120 minutes, respectively, and the data obtained were analyzed with CellQuest software.</p><p><b>RESULTS</b>The C-AM in the K562 and K562/VCR varied more apparently in the fist 24 hours. In addition, the MFI of the C-AM in K562 was significantly higher than that in K562/VCR cells indicating that the P-gp pump molecules were functioning. The MFIs of the CSA, VER and CSA + VER groups co-cultured with K562/VCR cells were 4014 +/- 219, 3879 +/- 116 and 4158 +/- 302, respectively after 120 min of incubation, significantly higher as compared to that of control group (3251 +/- 107, P < 0.05). On the other hand, significant inhibition of the efflux from the K562/VCR cell line was also noticed after the same time period of incubation with the MFIs of 2237 +/- 155, 1932 +/- 233 and 2231 +/- 147, respectively in the three groups, which was significantly higher than that of control group (1622 +/- 191, P < 0.05). CSA, VER and CSA + VER could increase the uptake and inhibit the efflux of C-AM by K562/VCR cells, while no evident influence on those functions inside the parental cell line K562 cells was noticed.</p><p><b>CONCLUSIONS</b>CSA, VER and CSA + VER could increase the uptake and reduce the efflux of C-AM by K562/VCR cells while no significant difference between the CSA + VER and CSA or VER was noticed. P-gp pump function and the effects of its reversal agents on leukemic cells can be rapidly and easily evaluated by using the C-AM and FCM.</p>

Establishment of murine cell line transfected with human CD14 gene / 中国实验血液学杂志

This study was aimed to construct the CD14 eukaryotic expression vector, establish the transgeneic CD14 positive cell line in order to facilitate the establishment of a mouse model of antibody targeting therapy for human acute monocytic leukemia (AML-M(5)). Total RNA extracted from peripheral blood mononuclear cells was treated with RNAase-free DNAase, the human CD14 gene was cloned and sequenced through the RT-PCR and T-A clone techniques. Eukaryotic expressional vector pcDNA3.1(+)/CD14 was constructed by cleaving with double restriction endonuleases and ligating with T4 ligase. A murine melanoma cell line B16 was transfected with the pcDNA3.1(+)/CD14 recombinant with Superfect transfection reagent. Positive clones were selected by G418 and the expression of human CD14 on the transfectant was confirmed by flow cytometry (FCM). The results indicated that the sequence of the human CD14 cDNA cloned was exact to be same as the one from GenBank database. The recombinant pcDNA3.1(+)/CD14 was identified with double-enzyme cleaving. The expression of the human CD14 on the transfectant (B16/CD14) was confirmed by FCM. In conclusion, the murine cell line B16/CD14 fransfected with human CD14 gene has been established which can be used for the study of human AML-M(5) antibody targeting therapy with mouse model.

Reactivity of a novel monoclonal antibody ZCH-7-2D3 on leukemia cells and its clinical significance / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To analyze the reactive pattern and its clinical significance of ZCH-7-2D3 monoclonal antibody on leukemia cells.</p><p><b>METHODS</b>Bone marrow samples from 100 leukemia patients (male 59: female 41, 34 cases of children and 66 adults, aged 11 months - 77 year) were collected. A CD45 gating strategy and multi-parameter flow cytometry were used to analyze the leukemia cells.</p><p><b>RESULT</b>The positive rate (10/31) of 2D3 antibody on acute lymphocytic leukemia (ALL) patients was significantly lower than that (39/55) of acute myelogeneous leukemia (AML) (P <0.01). 2D3 was positive for all three cases of B/myeloid mixed lineage leukemia, but negative in 6 cases of chronic myelogeneous leukemia (CML), significantly lower than that in AML (39/55, P<0.01) patients. There was no difference between the positive rates of chronic lymphocytic leukemia (CLL, 3/5) and B lineage ALL (9/28, P = 0.2389). The antibody was not found to recognize the differentiation stages of either ALL and AML subtypes.</p><p><b>CONCLUSION</b>2D3 monoclonal antibody primarily recognizes AML cases. Further studies on cloning of gene encoding the antigen protein and its biological functions are warranted.</p>

Comparison between CD19 and CD20 expression patterns on acute leukemic cells / 中国实验血液学杂志

In order to provide the evidences for CD19 as a better antibody targeting molecule for B lineage acute leukemias than CD20 through the multi-parameter flow-cytometry analysis of leukemia cells, the samples from 321 patients with acute leukemia (AL) were immunophenotyped by multi-color flow cytometry and CD45/SSC gating strategy followed by the analysis of CD19 and CD20 expression. The results showed that the positive rate of CD19 (115/116, 99.1%) in 116 cases with B lineage acute lymphoblastic leukemia (B lineage ALL) was significantly higher than that of CD20 (33/116, 28.4%) (P < 0.01); in 17 patients with B lineage/Myeloid (B/My) acute mixed lineage leukemia (AMLL), the former positive rate (17/17, 100%) was also higher than the latter (5/17, 29.4%) (P < 0.01). Both of the two antigens were negative in 29 patients with acute T lymphoblastic leukemia and 7 patients with T/My AMLL. The positive rates of CD19 and CD20 in 152 patients with acute myeloid leukemia (AML) were 7.2% and 2.0%, respectively. The difference of the fluorescence intensity between the two antigens on the cells from each patient with B lineage ALL or B/My AMLL was statistically significant (t = 20.68, P < 0.001). The specificity of CD19 and CD20 in B lymphocytic lineage was 92.3% (132/143) and 92.7% (38/41), respectively, while the sensitivity was 99.2% (132/133) and 28.6% (38/133), respectively, the former sensitivity was significantly higher than the latter (chi(2) = 144.018, P = 0.001). It is concluded that CD19 continuously and steadily express on almost all subtypes of B lineage leukemic cells with homogeneous pattern while only a small number of leukemias express CD20. Both the specificity and sensitivity of CD19 were very high with a much broader reaction pattern than that of CD20 on this group of diseases. These indicate that CD19 may be a better antibody targeting molecule than CD20 for patients with B-lineage acute leukemia.

Preparation and characterization of a directly labeled mouse anti-human CD14 monoclonal antibody ZCH-2F9-FITC / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To prepare fluorescein isothiocyanate (FITC) directly conjugated to monoclonal antibody (McAb) anti-human CD14, ZCH-7-2F9 (2F9-FITC).</p><p><b>METHODS</b>After generation and purification, the purity and the murine immunoglobulin subtype of the antibody were evaluated with SDS-PAGE and multicolor flow cytometry (FCM). 2F9 McAb was directly labeled with FITC through modified Marsshall's method and the positive rate of the 2F9-FITC on different types of leukemic cells were compared with the standard CD14-FITC by FCM.</p><p><b>RESULT</b>A large quantity of purified 2F9 McAb was prepared. The subtype of 2F9 was murine IgG1kappa. 2F9-FITC was successfully manufactured with A295/A280 ratio of 0.44. The positive cell percentages of 2F9-FITC and CD14-FITC on the monocytes were 84.50% and 90.08%, respectively, while those on lymphocytes were only 0.52% and 1.01%. There was no significant difference between the CD14 expressions with 2F9-FITC and CD14-FITC on each type of leukemia (n=23, t=0.922, P=0.367).</p><p><b>CONCLUSION</b>2F9-FITC has been successfully prepared and it can be applied in diagnosis and differentiation of monoblastic leukemias.</p>

The expression of CD19 in 210 cases of childhood acute leukemia and its significance / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the expression of CD19 on childhood acute leukemia (AL) and its significance, and to provide evidence for the diagnosis and differential diagnosis as well as monoclonal antibody-targeting treatment of leukemia.</p><p><b>METHODS</b>There were 210 cases of childhood AL, of which 130 cases were male and 80 were female with a mean age of 9 years old. Using a panel of 27 fluorochrome directly labeled monoclonal antibodies, 210 samples from the patients were analyzed with CD45/SSC double parameters and multi-color flow cytometry to determine the expression of CD19.</p><p><b>RESULTS</b>In the 93 cases of B lineage acute lymphoblastic leukemia (ALL), the positive rate (98.9%, 92/93) of CD19 was significantly higher than that of the other B cell related antigens, such as CD10 (88.2%, 82/93, P = 0.003), CD20 (24.7%, 23/93, P = 0.001) and CD22 (60.2%, 56/93, P = 0.001). CD19 was expressed on all 8 cases of B/myeloid (My) hybrid acute leukemia (HAL) and 1 case of B/T HAL, but was not expressed on all 24 cases of T lineage leukemia and 5 cases of T/My HAL. In the 79 cases of acute myeloid leukemia (AML), only 5 (6.3%) cases expressed CD19. The positive rate (6.3%) of CD19 on AML was significantly lower than that on B lineage ALL (98.9%, P = 0.001). The percentage of CD19 positive cells in B/My HAL (41.6% - 88.7% with a mean of 73.8%) was significant higher than that in CD19(+)-AML (21.4% - 50.4% with a mean of 24.2%; Run Sum test, P = 0.0084). Of the 210 cases, 102 were B lineage related AL including B lineage ALL, B/My HAL and B/T HAL. In B lineage related AL, the sensitivity and the specificity of CD19 was 99.0% (101/102) and 95.4% (13/108) while the positive predictive and the negative predictive values to B lineage were 95.3% (101/106) and 99.0% (103/104), respectively. Using CD19(+) as a single reagent to diagnose B lineage, the false positive rate was 4.6% (5/108) and the false negative rate was 1.0% (1/102) with a general diagnosis index (GDI) of 94.4% [GDI = 1-(false positive rate + false negative rate)].</p><p><b>CONCLUSION</b>CD19 is continuously and stably expressed on all stages of B lineage differentiation. It is a reliable cell membrane marker for diagnosing B lineage ALL and an ideal target for antibody-targeting treatment of leukemia as well; the expression degree of CD19 can be used to distinguish B/My HAL from CD19(+)-AML; CD19 didn't express on normal myeloid cells but did on some AML cells. Therefore it can be used to detect the minimal residual disease.</p>

Expression of leucocyte cell-surface antigens on colon cancer cell line HR8348 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To define the immune phenotype of colon cancer cells.</p><p><b>METHODS</b>Using a panel of 40 anti-human monoclonal antibodies (MoAbs), the cells of colon cancer HR8348 were analyzed with three-color flow cytometry after direct immunofluorescent staining.</p><p><b>RESULTS</b>HR8348 cell line did not express CD2, CD3, CD4, CD5, CD7, CD8, TCR, CD10, CD11b, CD14, CD16, CD19, CD22, CD25, CD28, SmIg, CD33, CD35, CD36, CD41a, CD45, CD45RA, CD45RO, CD56, CD61, CD64, CD66b, CD69, CD71, CD117, CD122 and P-glycoprotein but expressed CD13, CD15, CD20, CD38, CD95 and HLA-DR.</p><p><b>CONCLUSION</b>The results demonstrate that colon cancer cell line HR8348 shares some antigenic determinants with leucocyte lineage.</p>